End-to-end (e2e) service level agreement (SLA) compliance across both managed and unmanaged network segments

ABSTRACT

Embodiments of the present invention address deficiencies of the art in respect to e2e SLA support in a network of both manageable and unmanageable portions and provide a method, system and computer program product for e2e SLA compliance across both managed and unmanaged network segments. In one embodiment of the invention, a method for e2e SLA compliance across both managed and unmanaged network segments can be provided. The method can include identifying both a managed segment and an unmanaged segment of an e2e network for a communications path implicated by an SLA, determining an observed delay for the unmanaged segment of the e2e network, computing from a desired delay for the communications path and the observed delay a differential delay, and constraining the managed segment to meet the differential delay in order to assure meeting the desired delay for the communications path implicated by the SLA.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to differentiated service in a computercommunications network and more particularly to end-to-end (e2e) servicelevel agreement (SLA) compliance.

2. Description of the Related Art

The modern global network can be viewed as a complex interweaving ofmultiple network technologies, server platforms, client capabilities andapplication requirements. The vast majority of network technologieshandle device requests indiscriminately. That is, regardless of theidentity of the requester or the type of request, each device requestcan be processed with equal priority. Given the exponential increase innetwork traffic across the Internet, however, more recentnetwork-oriented computing devices have begun to provide varying levelsof computing services based upon what has been referred to as a “policybased service differentiation model”.

In a policy based service differentiation model, the computing devicescan offer many levels of service where different requests for differentcontent or services which originate from different requesters receivedifferent levels of treatment depending upon administratively definedpolicies. In this regard, a service level agreement (SLA) can specify aguaranteed level of responsiveness based upon a pre-defined policy. Moreparticularly, the SLA is a contract that specifies an agreement betweena service provider and customer regarding a level of service to beprovided by the service provider to the customer in respect to aspecific resource.

Within the modern enterprise, the enterprise can receive a substantialbenefit for effectively providing differentiated service to differentcustomers and different data so that some customers and data receive ahigher level of service than other customers and data on the network.That is to say, where the enterprise satisfies the expected servicelevel of a valued customer, the enterprise can retain the customer.Conversely, where the enterprise fails to satisfy the expected level ofservice of a valued customer, the enterprise likely can lose thecustomer. Hence, differentiated service can be an important component ofe-commerce inasmuch as a customer always can be viewed as merely “oneclick away” from a competitor's system where response times falter.

Accordingly, the enforcement of the terms of an SLA can be of paramountimportance in managing the customer service relationship. To that end,service level management systems have become commonplace in theenterprise. A service level management system can track servicesprovided to customers and compare the delivery of services to theservice terms of a corresponding SLA. Performance metrics can becollected over time in respect to the resources associated with the SLAand the metrics can be evaluated to determine if any of the terms of theSLA have been violated.

The application of an SLA to a manageable network involves the tuning ofthe elements of the manageable network to achieve the performanceguaranteed by the SLA. Generally, the performance guaranteed by an SLArelates in some way to an acceptable average delay demonstrated by themanageable network. In an end to end (e2e) network environment, however,the communications path between two endpoints can traverse bothmanageable portions of a network and unmanageable portions of a network.As such, tuning the components of the e2e network environmentnecessarily is limited to a best guess approach to providing extremelyconservative restraints on the manageable portion of the e2e network anda loosing of terms in a corresponding e2e SLA.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present invention address deficiencies of the art inrespect to e2e SLA support in a network of both manageable andunmanageable portions and provide a novel and non-obvious method, systemand computer program product for e2e SLA compliance across both managedand unmanaged network segments. In one embodiment of the invention, amethod for e2e SLA compliance across both managed and unmanaged networksegments can be provided. The method can include identifying both amanaged segment and an unmanaged segment of an e2e network for acommunications path implicated by an SLA, determining an observed delayfor the unmanaged segment of the e2e network, computing from a desireddelay for the communications path and the observed delay a differentialdelay, and constraining the managed segment to meet the differentialdelay in order to assure meeting the desired delay for thecommunications path implicated by the SLA.

In one aspect of the embodiment, computing from a desired delay for thecommunications path and the observed delay a differential delay caninclude subtracting the observed delay from the desired delay to producethe differential delay. In another aspect of the embodiment,constraining the managed segment to meet the differential delay in orderto assure meeting the desired delay for the communications pathimplicated by the SLA can include ordering each of different sub-domainsin the managed segment according to a minimum delay each of thedifferent sub-domains can achieve, and allocating portions of thedifferential delay according to the ordering so that a sub-domain ableto achieve a least minimum delay is allocated a greatest portion of thedifferential delay while a sub-domain able to achieve a greatest minimumdelay is allocated a least portion of the differential delay.

In another embodiment of the invention, an e2e SLA compliance dataprocessing system can be provided. The system can include a provisioninghost coupled to an e2e network comprising both managed and unmanagedsegments and SLA compliance logic executing in the host. The logic caninclude program code enabled to identify at least one of the managedsegments and at least one of the unmanaged segments of an e2e networkfor a communications path implicated by an SLA, to determine an observeddelay for the at least one unmanaged segment, to compute from a desireddelay for the communications path and the observed delay a differentialdelay, and to constrain the managed segment to meet the differentialdelay in order to assure meeting the desired delay for thecommunications path implicated by the SLA.

Additional aspects of the invention will be set forth in part in thedescription which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. The aspectsof the invention will be realized and attained by means of the elementsand combinations particularly pointed out in the appended claims. It isto be understood that both the foregoing general description and thefollowing detailed description are exemplary and explanatory only andare not restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute partof this specification, illustrate embodiments of the invention andtogether with the description, serve to explain the principles of theinvention. The embodiments illustrated herein are presently preferred,it being understood, however, that the invention is not limited to theprecise arrangements and instrumentalities shown, wherein:

FIG. 1 is a schematic illustration of an e2e network environmentconfigured for e2e SLA compliance across both managed and unmanagednetwork segments; and,

FIG. 2 is a flow chart illustrating a process for e2e SLA complianceacross both managed and unmanaged network segments of an e2e networkenvironment.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention provide a method, system andcomputer program product for e2e SLA compliance across both managed andunmanaged network segments. In accordance with an embodiment of thepresent invention, a requisite path of communications in an e2e networkenvironment can be determined for a participant to an SLA and one ormore managed and unmanaged segments of the e2e network environmenttraversed by the path of communications can be identified. An observeddelay budget for the identified unmanaged segments can be establishedand a composite delay budget for the e2e network environment can beestablished according to the SLA. Finally, a differential delay budgetaccounting for the composite delay budget and the observed delay budgetcan be computed for the managed segments. Thereafter, the individualsub-domains in the managed segments can be constrained to accommodatethe differential delay budget to meet the composite delay budget underthe SLA for the e2e network environment.

In further illustration, FIG. 1 is a schematic illustration of an e2enetwork environment configured for e2e SLA compliance across bothmanaged and unmanaged network segments. As shown in FIG. 1, an e2enetwork environment can include two endpoints 110 communicativelycoupled to one another over a computer communications network 120. Thecomputer communications network 120 can include one or more managedsegments 160 and one or more unmanaged segments 170. Each of the managedsegments 160 can include one or more managed sub-domains D(M). Likewise,each of the unmanaged segments 170 can include one or more unmanagedsub-domains D(U).

A provisioning host 130 can be coupled to the computer communicationsnetwork 120. The provisioning host 130 can be configured to manage theprovisioning of the managed sub-domains D(M) in the managed segments160. The provisioning host 130 further can be configured to observe eachof the managed segments 160 and the unmanaged segments 170 in order torecord observed delays in transactions between the endpoints 110.Finally, the provisioning host 130 can be coupled to SLA compliancelogic 140.

The SLA compliance logic 140 can include program code enabled tostrategically provision the managed sub-domains D(M) in order to meet adelay budget 150 provided by an SLA for the endpoints 110. In thisregard, the delay budget 150 can be reduced by an observed delay for theunmanaged segment 170 in order to compute a differential delay budget.Once computed, the differential delay budget can be applied to themanaged segment 160 in order to appropriately provision the managedsub-domains D(M). In this way, the delay budget 150 for the SLA can bemet despite an inability to manage the managed sub-domains D(U) of theunmanaged segment 170 of the computer communications network.

In yet further illustration, FIG. 2 is a flow chart illustrating aprocess for e2e SLA compliance across both managed and unmanaged networksegments of an e2e network environment. Beginning in block 210, thesub-domains of both managed and unmanaged segments of an e2e network canbe catalogued. Thereafter, in block 220 the communications path acrossthe e2e network implicated by an SLA can be determined and in block 230,particular ones of both the sub-domains on the managed segment and alsothe sub-domains on the unmanaged segment of the e2e network for thecommunications path can be identified.

In block 240, a desired delay budget 240 for the SLA can be established.Alternatively, a loss metric or other such metric for the SLA can beestablished. Also, in block 250 an observed required delay budget forthe sub-domains of the unmanaged segment of the e2e network implicatedby the communications path can be determined. In the alternative, arequired loss metric budget for the sub-domains of the unmanaged segmentof the e2e network implicated by the communications path can bedetermined. Consequently, a differential budget can be computed in block260 as the difference between the established delay budget and theobserved required delay budget, or the different in the established lossmetric and the required loss metric. The differential can be used, then,for provisioning the sub-domains of the managed segment of the e2enetwork implicated by the communications path.

In block 270, the sub-domains in the managed segment of the e2e networkimplicated by the communications path can be ordered from mostconstrained to least constrained. Specifically, the sub-domains can beordered in terms of the minimum delay (or minimum loss metric or othersuch metric) that each sub-domain can satisfy in order to meet thepolicy requirements for resource provisioning. Thereafter, in block 280,the sub-domains of the managed segment of the e2e network implicated bythe communications path can be constrained according to a portion of thedifferential delay budget allocated to each of the sub-domains. Forexample, using a “Greedy” algorithm, the differential budget can bepartitioned so that the most constrained sub-domain is allocated thegreatest portion of the differential delay budget and so forth.

Finally, the process can repeat through block 240 in the event of asignificant change in network performance for the SLA, or a significantchange in network load along other communications paths implicated bythe SLA. Embodiments of the invention can take the form of an entirelyhardware embodiment, an entirely software embodiment or an embodimentcontaining both hardware and software elements. In a preferredembodiment, the invention is implemented in software, which includes butis not limited to firmware, resident software, microcode, and the like.Furthermore, the invention can take the form of a computer programproduct accessible from a computer-usable or computer-readable mediumproviding program code for use by or in connection with a computer orany instruction execution system.

For the purposes of this description, a computer-usable or computerreadable medium can be any apparatus that can contain, store,communicate, propagate, or transport the program for use by or inconnection with the instruction execution system, apparatus, or device.The medium can be an electronic, magnetic, optical, electromagnetic,infrared, or semiconductor system (or apparatus or device) or apropagation medium. Examples of a computer-readable medium include asemiconductor or solid state memory, magnetic tape, a removable computerdiskette, a random access memory (RAM), a read-only memory (ROM), arigid magnetic disk and an optical disk. Current examples of opticaldisks include compact disk—read only memory (CD-ROM), compactdisk—read/write (CD-R/W) and DVD.

A data processing system suitable for storing and/or executing programcode will include at least one processor coupled directly or indirectlyto memory elements through a system bus. The memory elements can includelocal memory employed during actual execution of the program code, bulkstorage, and cache memories which provide temporary storage of at leastsome program code in order to reduce the number of times code must beretrieved from bulk storage during execution. Input/output or I/Odevices (including but not limited to keyboards, displays, pointingdevices, etc.) can be coupled to the system either directly or throughintervening I/O controllers. Network adapters may also be coupled to thesystem to enable the data processing system to become coupled to otherdata processing systems or remote printers or storage devices throughintervening private or public networks. Modems, cable modem and Ethernetcards are just a few of the currently available types of networkadapters.

1. A method, within a data processing system comprising a provisioninghost, for end to end (e2e) service level agreement (SLA) complianceacross both managed and unmanaged network segments, the methodcomprising: identifying, using the provisioning host, both a managedsegment and an unmanaged segment of an e2e network for a communicationspath implicated by an SLA; determining, using the provisioning host, anobserved delay for the unmanaged segment of the e2e network; computing,using the provisioning host and from a desired delay for thecommunications path and the observed delay, a differential delay; and,constraining, using the provisioning host, the managed segment to meetthe differential delay in order to assure meeting the desired delay forthe communications path implicated by the SLA; wherein the constrainingcomprises: ordering each of different sub-domains in the managed segmentaccording to a minimum delay each of the different sub-domains canachieve; allocating portions of the differential delay according to theordering, wherein a sub-domain able to achieve a minimum delay lowerthan minimum delays of all the other sub-domains is allocated a greatestportion of the differential delay, and a sub-domain able to achieve aminimum delay greater than minimum delays of all the other sub-domainsis allocated a least portion of the differential delay.
 2. The method ofclaim 1, wherein the computing comprises subtracting the observed delayfrom the desired delay to produce the differential delay.
 3. The methodof claim 1, further comprising: detecting a material change in networkperformance in the e2e network; and, repeating the identifying,determining, computing and constraining in response to detecting thematerial change.
 4. The method of claim 1, further comprising: detectinga material change in network load in the e2e network; and, repeating theidentifying, determining, computing and constraining in response todetecting the material change.
 5. An end to end (e2e) service levelagreement (SLA) compliance data processing system comprising: aprovisioning host coupled to an e2e network comprising both managed andunmanaged segments; SLA compliance logic executing in the host, thelogic comprising program code enabled to identify at least one of themanaged segments and at least one of the unmanaged segments of an e2enetwork for a communications path implicated by an SLA, determine anobserved delay for the at least one unmanaged segment, compute, from adesired delay for the communications path and the observed delay, adifferential delay, and constrain the managed segment to meet thedifferential delay in order to assure meeting the desired delay for thecommunications path implicated by the SLA; wherein the constrainingcomprises: ordering each of different sub-domains in the managed segmentaccording to a minimum delay each of the different sub-domains canachieve; allocating portions of the differential delay according to theordering, wherein a sub-domain able to achieve a minimum delay lowerthan minimum delays of all the other sub-domains is allocated a greatestportion of the differential delay, and a sub-domain able to achieve aminimum delay greater than minimum delays of all the other sub-domainsis allocated a least portion of the differential delay.
 6. A computerprogram product comprising a non-transitory computer usable mediumembodying computer usable program code for end to end (e2e) servicelevel agreement (SLA) compliance across both managed and unmanagednetwork segments, the computer program product comprising computerusable program code, when executed by a data processing systemcomprising a provisioning host, for causing the data processing systemto perform: identifying both a managed segment and an unmanaged segmentof an e2e network for a communications path implicated by an SLA;determining an observed delay for the unmanaged segment of the e2enetwork; computing, from a desired delay for the communications path andthe observed delay, a differential delay; constraining the managedsegment to meet the differential delay in order to assure meeting thedesired delay for the communications path implicated by the SLA; whereinthe constraining comprises: ordering each of different sub-domains inthe managed segment according to a minimum delay each of the differentsub-domains can achieve; allocating portions of the differential delayaccording to the ordering, wherein a sub-domain able to achieve aminimum delay lower than minimum delays of all the other sub-domains isallocated a greatest portion of the differential delay, and a sub-domainable to achieve a minimum delay greater than minimum delays of all theother sub-domains is allocated a least portion of the differentialdelay.
 7. The computer program product of claim 6, wherein the computingcomprises subtracting the observed delay from the desired delay toproduce the differential delay.
 8. The computer program product of claim7, further comprising: detecting a material change in networkperformance in the e2e network; and, repeating the identifying,determining, computing and constraining in response to detecting thematerial change.
 9. The computer program product of claim 8, furthercomprising: detecting a material change in network load in the e2enetwork; and, repeating the identifying, determining, computing andconstraining in response to detecting the material change.